Turkey’s ruling and opposition parties have launched the final stretch of this year’s presidential campaign, with elections scheduled for Sunday, amid widespread concerns that President Recep Tayyip Erdogan will cruise to an easy win through irregular voting situations and possible election fraud.

To prevent undocumented election fraud, opposition groups have called for 519,000 volunteer election observers to station themselves throughout the country and ensure equal access to ballots for all, Reuters reported on Thursday, noting that 2015’s parliamentary election and 2017’s referendum on whether the country should switch from a parliamentary to a presidential government system were both followed by protests that Erdogan’s Islamist Justice and Development Party (AKP) had won on an uneven playing field.

The coalition of opposition parties participating in Sunday’s election told Reuters that the over half a million independent observers would monitor 180,000 polling stations.

Among the opposition parties running candidates on Sunday are the secularist Republican People’s Party (CHP) – the Republic of Turkey’s oldest party, founded by Mustafa Kemal Atatürk – the leftist, pro-Kurdish People’s Democratic Party (HDP), and the Iyi, or Good, Party, a new coalition made up of politicians who split from the Nationalist Movement Party (MHP).

The parties contend that, even without proof of outright election fraud on Sunday, Erdogan has rigged the game to his benefit. The HDP’s presidential candidate, for example, Selahattin Demirtaş, is in prison, awaiting trial on charges of aiding terrorists for having demanded that Ankara respect the human rights of Kurds in the nation’s south, who have lived under a state of quasi-martial law since the 2016 failed coup against Erdogan. Demirtaş has campaigned by sending messages to the public through his attorneys and his wife when allowed regular phone calls to her. Demirtaş smuggled an opinion piece out of prison, published in the New York Times this week, and on Thursday staged an “e-rally” to connect with supporters through Twitter.

“Hello! I wholeheartedly greet everyone who came to the rally grounds from around the world. For the first time in the world, an e-rally is being held from a prison cell. In other words, we are now making history regarding the world democracy. I have to state this so that the Anadolu agency breaks the news,” Demirtaş’ Twitter account read, his attorneys publishing his words for him. Demirtaş insisted in his New York Times piece that his lawyers have control of his account and that he has not smuggled a cell phone or any technology into his cell illegally.

The HDP rose to prominence in 2015, securing the over ten percent of the vote that parties need to be allotted representation in Parliament with a diverse array of religious and ethnic minority candidates. Erdogan promptly called a new election that November, claiming no party received a mandate to govern, and brought the HDP down to 10.4 percent of the vote. The HDP warns that the purpose of this election is to kill the party off completely, bringing the vote down to below ten percent.

Two years later, Erdogan called elections for a referendum on a presidential system. Erdogan’s side won – granting him unprecedented powers without the checks common in presidential systems like America’s – but not before changing elections laws last minute to allow for counting unverified ballots, a move that outraged the “no” contingent.

The HDP and CHP demanded recounts, but the vote ultimately stayed. Erdogan condemned European election monitors for expressing concern about the way the law was changed. Since then, the Turkish Parliament has passed a law that allows unstamped ballots to be counted in all cases.

Demirtaş and his party face the most egregious, but far from the only, obstacles opposition candidates have suffered to campaign. Following the failed coup in 2016, Erdogan’s regime shut down hundreds of media outlets unfavorable to the regime, sometimes violently sending police into live broadcast newsrooms and shutting down whole networks permanently.

The result has been a near-blackout of opposition candidates on Turkish television. Reuters notes that television watchdog RTUK recorded 67 hours of reporters on Erdogan and the AKP in the past month. CHP candidate Muharrem Ince was covered for seven hours that month; Demirtaş, a prisoner, did not appear on screen at all.

In the Kurdish south, the HDP alleges that the Turkish government is using brute force to ensure that voters who oppose Erdogan are either too far from their ballots to reasonably go vote or too threatened by the use of violence to vote against him.

“There is a state of emergency and it is implemented like martial law in the southeast. These elections will be held under the shadow of a gun,” HDP deputy chairwoman Yurdusev Ozsokmenler said.

Al-Monitor reported on Wednesday that police have also arrested dozens of HDP politicians and supporters in the past few weeks. This week, “more than 50 party members and canvassers were detained in separate early morning raids in the eastern province of Erzurum,” according to the outlet. Several others arrests have targeted “ballot box monitors,” Al-Monitor alleged.

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